mirror of
https://github.com/ByteWelder/Tactility.git
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294 lines
9.9 KiB
C++
294 lines
9.9 KiB
C++
// SPDX-License-Identifier: Apache-2.0
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#include <drivers/xpt2046_softspi.h>
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#include <xpt2046_softspi_module.h>
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#include <tactility/device.h>
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#include <tactility/driver.h>
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#include <tactility/drivers/gpio_controller.h>
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#include <tactility/drivers/pointer.h>
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#include <tactility/delay.h>
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#include <tactility/error.h>
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#include <tactility/log.h>
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#include <cstdlib>
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#define TAG "XPT2046SoftSPI"
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#define GET_CONFIG(device) (static_cast<const Xpt2046SoftSpiConfig*>((device)->config))
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namespace {
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constexpr uint8_t CMD_READ_X = 0xD0;
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constexpr uint8_t CMD_READ_Y = 0x90;
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constexpr int RAW_MIN_DEFAULT = 100;
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constexpr int RAW_MAX_DEFAULT = 1900;
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constexpr int RAW_VALID_MIN = 100;
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constexpr int RAW_VALID_MAX = 3900;
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constexpr int SAMPLE_COUNT = 8;
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} // namespace
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struct Xpt2046SoftSpiInternal {
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GpioDescriptor* mosi;
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GpioDescriptor* miso;
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GpioDescriptor* sck;
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GpioDescriptor* cs;
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bool swap_xy;
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bool mirror_x;
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bool mirror_y;
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bool touched;
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uint16_t x;
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uint16_t y;
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};
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// region Driver lifecycle
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static void release_descriptors(Xpt2046SoftSpiInternal* internal) {
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if (internal->mosi != nullptr) gpio_descriptor_release(internal->mosi);
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if (internal->miso != nullptr) gpio_descriptor_release(internal->miso);
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if (internal->sck != nullptr) gpio_descriptor_release(internal->sck);
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if (internal->cs != nullptr) gpio_descriptor_release(internal->cs);
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}
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static error_t start(Device* device) {
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const auto* config = GET_CONFIG(device);
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(malloc(sizeof(Xpt2046SoftSpiInternal)));
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if (internal == nullptr) {
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return ERROR_OUT_OF_MEMORY;
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}
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*internal = {};
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internal->mosi = gpio_descriptor_acquire(config->pin_mosi.gpio_controller, config->pin_mosi.pin, GPIO_OWNER_GPIO);
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internal->miso = gpio_descriptor_acquire(config->pin_miso.gpio_controller, config->pin_miso.pin, GPIO_OWNER_GPIO);
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internal->sck = gpio_descriptor_acquire(config->pin_sck.gpio_controller, config->pin_sck.pin, GPIO_OWNER_GPIO);
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internal->cs = gpio_descriptor_acquire(config->pin_cs.gpio_controller, config->pin_cs.pin, GPIO_OWNER_GPIO);
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if (internal->mosi == nullptr || internal->miso == nullptr || internal->sck == nullptr || internal->cs == nullptr) {
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LOG_E(TAG, "Failed to acquire GPIO descriptors");
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release_descriptors(internal);
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free(internal);
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return ERROR_RESOURCE;
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}
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bool ok =
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gpio_descriptor_set_flags(internal->mosi, GPIO_FLAG_DIRECTION_OUTPUT) == ERROR_NONE &&
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gpio_descriptor_set_flags(internal->sck, GPIO_FLAG_DIRECTION_OUTPUT) == ERROR_NONE &&
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gpio_descriptor_set_flags(internal->cs, GPIO_FLAG_DIRECTION_OUTPUT) == ERROR_NONE &&
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gpio_descriptor_set_flags(internal->miso, GPIO_FLAG_DIRECTION_INPUT | GPIO_FLAG_PULL_UP) == ERROR_NONE;
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// Idle state: CS high (deselected), SCK/MOSI low.
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ok = ok &&
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gpio_descriptor_set_level(internal->cs, true) == ERROR_NONE &&
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gpio_descriptor_set_level(internal->sck, false) == ERROR_NONE &&
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gpio_descriptor_set_level(internal->mosi, false) == ERROR_NONE;
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if (!ok) {
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LOG_E(TAG, "Failed to configure GPIO pins");
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release_descriptors(internal);
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free(internal);
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return ERROR_RESOURCE;
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}
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internal->swap_xy = config->swap_xy;
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internal->mirror_x = config->mirror_x;
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internal->mirror_y = config->mirror_y;
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device_set_driver_data(device, internal);
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return ERROR_NONE;
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}
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static error_t stop(Device* device) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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release_descriptors(internal);
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free(internal);
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return ERROR_NONE;
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}
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// endregion
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// region Bit-banged SPI
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// XPT2046 protocol: 8-bit command out, 12-bit conversion result back (MSB first), clocked
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// manually since no hardware SPI peripheral is available for this pin set (see the binding's
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// description). 1us clock half-period is well within the XPT2046's timing budget (it's rated
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// for a multi-MHz SPI clock; this bit-bang loop runs orders of magnitude slower).
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static int read_spi_command(Xpt2046SoftSpiInternal* internal, uint8_t command) {
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int result = 0;
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gpio_descriptor_set_level(internal->cs, false);
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delay_micros(1);
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for (int i = 7; i >= 0; i--) {
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gpio_descriptor_set_level(internal->mosi, (command & (1 << i)) != 0);
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gpio_descriptor_set_level(internal->sck, true);
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delay_micros(1);
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gpio_descriptor_set_level(internal->sck, false);
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delay_micros(1);
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}
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for (int i = 11; i >= 0; i--) {
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gpio_descriptor_set_level(internal->sck, true);
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delay_micros(1);
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bool level = false;
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gpio_descriptor_get_level(internal->miso, &level);
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if (level) {
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result |= (1 << i);
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}
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gpio_descriptor_set_level(internal->sck, false);
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delay_micros(1);
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}
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gpio_descriptor_set_level(internal->cs, true);
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return result;
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}
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// endregion
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// region PointerApi
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static error_t xpt2046_softspi_enter_sleep(Device*) {
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// No software-controlled power-down for this bit-banged variant; nothing to do.
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_exit_sleep(Device*) {
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return ERROR_NONE;
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}
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// Takes and averages several raw samples (rejecting out-of-range noise) then maps them onto
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// [0, x_max]/[0, y_max], applying swap/mirror. Mirrors the deprecated HAL's Xpt2046SoftSpi driver.
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static error_t xpt2046_softspi_read_data(Device* device, TickType_t timeout) {
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(void)timeout;
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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const auto* config = GET_CONFIG(device);
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int total_x = 0;
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int total_y = 0;
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int valid_samples = 0;
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for (int i = 0; i < SAMPLE_COUNT; i++) {
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const int raw_x = read_spi_command(internal, CMD_READ_X);
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const int raw_y = read_spi_command(internal, CMD_READ_Y);
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if (raw_x > RAW_VALID_MIN && raw_x < RAW_VALID_MAX && raw_y > RAW_VALID_MIN && raw_y < RAW_VALID_MAX) {
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total_x += raw_x;
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total_y += raw_y;
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valid_samples++;
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}
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delay_millis(1);
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}
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if (valid_samples < 3) {
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internal->touched = false;
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return ERROR_NONE;
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}
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const int raw_x = total_x / valid_samples;
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const int raw_y = total_y / valid_samples;
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int mapped_x = (raw_x - RAW_MIN_DEFAULT) * static_cast<int>(config->x_max) / (RAW_MAX_DEFAULT - RAW_MIN_DEFAULT);
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int mapped_y = (raw_y - RAW_MIN_DEFAULT) * static_cast<int>(config->y_max) / (RAW_MAX_DEFAULT - RAW_MIN_DEFAULT);
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if (internal->swap_xy) {
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const int swapped = mapped_x;
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mapped_x = mapped_y;
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mapped_y = swapped;
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}
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if (internal->mirror_x) {
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mapped_x = static_cast<int>(config->x_max) - mapped_x;
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}
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if (internal->mirror_y) {
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mapped_y = static_cast<int>(config->y_max) - mapped_y;
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}
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if (mapped_x < 0) mapped_x = 0;
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if (mapped_x > static_cast<int>(config->x_max)) mapped_x = static_cast<int>(config->x_max);
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if (mapped_y < 0) mapped_y = 0;
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if (mapped_y > static_cast<int>(config->y_max)) mapped_y = static_cast<int>(config->y_max);
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internal->x = static_cast<uint16_t>(mapped_x);
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internal->y = static_cast<uint16_t>(mapped_y);
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internal->touched = true;
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return ERROR_NONE;
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}
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static bool xpt2046_softspi_get_touched_points(Device* device, uint16_t* x, uint16_t* y, uint16_t* strength, uint8_t* point_count, uint8_t max_point_count) {
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(void)strength;
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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if (!internal->touched || max_point_count < 1) {
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*point_count = 0;
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return false;
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}
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*x = internal->x;
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*y = internal->y;
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*point_count = 1;
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return true;
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}
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static error_t xpt2046_softspi_set_swap_xy(Device* device, bool swap) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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internal->swap_xy = swap;
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_get_swap_xy(Device* device, bool* swap) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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*swap = internal->swap_xy;
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_set_mirror_x(Device* device, bool mirror) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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internal->mirror_x = mirror;
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_get_mirror_x(Device* device, bool* mirror) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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*mirror = internal->mirror_x;
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_set_mirror_y(Device* device, bool mirror) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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internal->mirror_y = mirror;
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return ERROR_NONE;
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}
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static error_t xpt2046_softspi_get_mirror_y(Device* device, bool* mirror) {
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auto* internal = static_cast<Xpt2046SoftSpiInternal*>(device_get_driver_data(device));
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*mirror = internal->mirror_y;
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return ERROR_NONE;
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}
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// endregion
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static const PointerApi xpt2046_softspi_pointer_api = {
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.enter_sleep = xpt2046_softspi_enter_sleep,
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.exit_sleep = xpt2046_softspi_exit_sleep,
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.read_data = xpt2046_softspi_read_data,
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.get_touched_points = xpt2046_softspi_get_touched_points,
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.set_swap_xy = xpt2046_softspi_set_swap_xy,
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.get_swap_xy = xpt2046_softspi_get_swap_xy,
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.set_mirror_x = xpt2046_softspi_set_mirror_x,
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.get_mirror_x = xpt2046_softspi_get_mirror_x,
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.set_mirror_y = xpt2046_softspi_set_mirror_y,
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.get_mirror_y = xpt2046_softspi_get_mirror_y,
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};
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Driver xpt2046_softspi_driver = {
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.name = "xpt2046_softspi",
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.compatible = (const char*[]) { "xptek,xpt2046-softspi", nullptr },
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.start_device = start,
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.stop_device = stop,
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.api = &xpt2046_softspi_pointer_api,
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.device_type = &POINTER_TYPE,
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.owner = &xpt2046_softspi_module,
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.internal = nullptr
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};
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